a. With the aid of appropriate sketches and
thermodynamic analysis, describe the stages
of a typical Carnot cycle
b. 0.82 kg of air (ideal gas) executes a Carnot power cycle having
a thermal efficiency of 34 percent. The heat transfer to the air
during the isothermal expansion is 82 kJ. At the
In: Mechanical Engineering
4) A refrigerator in the kitchen at 30 ° C keeps the food section at -12 ° C. Refrigerant R-134a enters the evaporator located at the back of the freezer section of a home refrigerator with a degree of dryness of 100 kPa and 20 percent and exits at 100 kPa and -20 ° C. Since the compressor consumes 600 W and the COP of the refrigerator is 2.5, a) calculate the minimum flow (kW) required to keep the mass flow of the refrigerant, b) the heat released into the kitchen air (kW), c) the food section at -12 ° C. (20 point)
In: Mechanical Engineering
3) Air enters a compressor at 2 m / s, 20 ° C and 100 kPa pressure, exits at 50 m / s, 900 kPa pressure and 200 ° C. Make sure that the power consumed by the compressor is 500 kW. The outlet cross-section diameter of the compressor is 10 cm. (Neglect the change in potential energy.) (15 points)
CALCULATE THE AMOUNT OF HEAT?
In: Mechanical Engineering
Define the following terms,
(i) specific work transfer
(ii) specific air consumption
(iii) work ratio
(iv) swept volume
b. DerivetheformulaforthemeaneffectivepressureoftheOttocycle
c. An engine of 200 mm bore and 315 mm stroke works on Otto Cycle.
The clearance is
3O
0.00251 m . The initial pressure and temperature are 1 bar and 65
C. If the maximum
pressure is limited to 35 bar, calculate the following,
(i) The air standard efficiency of the cycle
(ii) The mean effective pressure for the cycle
In: Mechanical Engineering
A power station uses Diesel as fuel (C12H26), from the analysis of combustion gases, it's obtain that 30% of carbon is converted to CO and the rest to CO2.
Furthermore, the gases in the exhaust have a temperature of 450 K. with this information:
a) mass air-fuel ratio: In Kgair/Kgfuel
b) Theoric air percentage: %
c) Moles of water steam produced in the reaction: in kmol
d)"wasted" heat in the gases on the steam exhaust, if you consider that the ideal exit temprature of the combustion gases should be of 380K: in kJ/kg
In: Mechanical Engineering
i need summary between (4-10) pages about ((Control circuit refrigeration system in airplanes)) with name of the references in end page
In: Mechanical Engineering
Two equal gear wheel of 360 mm p.c.d and 6 module are in mesh if the pressure angle 20 determine the maximum addendum necessary if there are always to be at least two pairs of teeth in contact . if the gear wheels rorates at 110 r.p.m and 6 kw is being transmetted find the normal force between the teeth assuming that the total force is dividing equally between the two pairs of teeth Neglect the frection. (Ans 6.8mm , 1.54KN .)
In: Mechanical Engineering
Briefly describe (with the use of diagrams) the Brayton’s cycle and
derive the formula for
the coefficient of performance for the Brayton’s cycl
In: Mechanical Engineering
A house that is losing heat to the 100C outdoors at an average
rate of 50,000 kJ/h is maintained at 220C at all
times during a winter night for 10 h. The house is to be heated by
50 glass containers each containing 20 L
(1L=10-3 m3
) of water that is heated to 80oC during the day by a solar heater.
A thermostat-controlled 15-kW
back-up electric resistance heater turns on whenever necessary to
keep the house at 220C. Analyse and
determine the following:
i. If the average solar intensity is 650 W/m2
and the solar heater has an efficiency of 80%, calculate the
area of solar heater to heat 20L of water from 220C to 800C in 8
hours.
ii. How long did the electric heating system run at night?
iii. Keeping 2nd law of thermodynamics in mind, what is the maximum
efficiency of the back-up heater?
iv. If the heat provided by the back-up heater is provided using
Carnot heat pump, determine the
reduction in electricity consumption.
In: Mechanical Engineering
Derive the general energy equation for the following
systems using appropriate diagrams,
(i) Internal combustion engine
(ii) Steam turbine
(iii) Boiler
(iv) Compressor
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A machine is out of order for minor work. Define
controls
exercised in maintenance. Department required for its
maintenance.
In: Mechanical Engineering
ppt presentation on "Lifting Hazards"
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b Explain and discuss Deming’s philosophy of overall quality and reliability cost minimization.
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Obtain the initial and residual shock spectra of a half sine pulse. What is the total shock spectrum?
In: Mechanical Engineering
need a presentation on "Lifting Hazards"
In: Mechanical Engineering